tests/: update __future__ imports

TN: Q223-029

testsuite/tests/python-api/ghost_nodes/main.py

@@ -1,3 +1,6 @@
+from __future__ import (absolute_import, division, print_function,
+                        unicode_literals)
+
 import libfoolang
 
 
@@ -10,4 +13,4 @@ for node in unit.root.findall(lambda _: True):
     ))
     assert not node.text or not node.is_ghost
 
-print 'Done.'
+print('Done.')

testsuite/tests/python-api/ghost_nodes/test.py

@@ -2,6 +2,9 @@
 Test the handling of analysis units in the properties DSL.
 """
 
+from __future__ import (absolute_import, division, print_function,
+                        unicode_literals)
+
 import os.path
 
 from langkit.compiled_types import ASTNode, Field, T, root_grammar_class
@@ -44,4 +47,4 @@ foo_grammar.add_rules(
     ),
 )
 build_and_run(foo_grammar, 'main.py')
-print 'Done'
+print('Done')

testsuite/tests/python-api/node_negative_index/main.py

@@ -1,3 +1,6 @@
+from __future__ import (absolute_import, division, print_function,
+                        unicode_literals)
+
 import libfoolang
 
 

testsuite/tests/python-api/node_negative_index/test.py

@@ -3,6 +3,9 @@ Test the handling of negative indexes in the Python binding of AST nodes child
 getters.
 """
 
+from __future__ import (absolute_import, division, print_function,
+                        unicode_literals)
+
 import os.path
 
 from langkit.compiled_types import ASTNode, Field, T, root_grammar_class
@@ -31,4 +34,4 @@ foo_grammar.add_rules(
     name=Name(Tok(Token.Identifier, keep=True)),
 )
 build_and_run(foo_grammar, 'main.py')
-print 'Done'
+print('Done')